Physical, emotional, and mental fitness ensure longevity and quality life via the prevention of chronic health conditions and aging. Specific or task-oriented fitness training enhances performance in routine work. Athletes and fire fighters and police officials are trained to work aerobically and their endurance is built-up to a maximum. Even fire fighters and police officers undergo regular fitness tests designed to determine whether or not they are capable of the physically demanding tasks. General health and fitness is concerned with threats to the overall health of a community. There are sub-fields, like bio-statistics and epidemiology that analyze social and behavioral health.